CHARLOTTE, N.C. — When Hideki Matsuyama climbed the 48 steps from the Quail Hollow practice green to the first tee on Saturday, he took them two at a time, as if to show that the lead he held halfway through the P.G.A. Championship was not weighing heavily on him.

Since he made the cut at the Masters as a teenager in 2011, Matsuyama has been expected in his homeland, Japan, to become the first player from the country to win a men’s major. Six years later, the expectation of Matsuyama’s coronation hung over the course, as though balloons and confetti were ready to be released from the cover of clouds.

But the bounce in Matsuyama’s step could not hide his nerves, which revealed themselves in several loose swings in his round of two-over-par 73. Going into Sunday’s final round, he is tied for second with Chris Stroud (72) at six under over all, a stroke behind Kevin Kisner, who carded a 72 on Saturday.

“I’m disappointed the way I played today,” Matsuyama said through an interpreter. He added, “Probably the pressure had to do with it.”

Matsuyama, the third-ranked player in the world, was coming off a win six days earlier at a World Golf Championships event in Ohio, where he closed with a 61. On Friday, he had carded a bogey-free 64.

The fans swarming the course were not going to see the American Jordan Spieth complete a career grand slam, but it appeared they still might be witnesses to history.

“I think Hideki, with the way he’s been playing, his misses seem to be birdies right now,” Spieth said after an even-par 71 that left him hopelessly out of range of the leaders. He added: “When you have it going, you have it going. He’s going to be tough to beat.”

Spieth has spent his share of time facing outsize expectations. Yet he acknowledged that he could not relate to what the 25-year-old Matsuyama must be feeling.

“It’s hard for me to speak to the pressure he could feel winning the first major for his country,” said Spieth, who also talked honestly after his round about the degree of difficulty this major poses for him.

“I feel like my game truly suits the other three majors maybe more than a P.G.A. Championship,” said Spieth, whose only top 10 in this tournament in four previous starts was a second-place finish in 2015. “But I believe we can play anywhere and win anywhere. It’s just a matter of having everything in sync at the right time.”

Matsuyama, who has won six times worldwide in the past 10 months, was out of sync from the moment he reached the top of those 48 steps from the practice green. His opening drive landed in the right rough, and his right arm flew off the club during his follow through. Matsuyama’s streak of 22 holes without a bogey ended on No. 1 when he missed a 6-foot par putt.

“The worries that I had about my swing showed up today in the way I played,” Matsuyama said.

He was in the final grouping with Kisner and Jason Day, who has gotten to know Matsuyama while playing alongside him in two Presidents Cups. Last Sunday, Day sent Matsuyama a text message that read: “Congrats, mate. Unreal playing. See you next week.” On Friday, Day described Matsuyama as “a really good guy” who is the “hardest worker out here right now.”

Matsuyama’s swing tempo is the envy of his competitors. But playing Saturday in humidity that was only slightly more oppressive than the expectations placed on him, Matsuyama struggled to find his rhythm. He found just two fairways on the front nine.

If Matsuyama appeared to be mentally drained, it might have been because he had talked long into Friday night about his round of 64. He submitted to at least seven television interviews with crews from Japan, Europe and the United States. He sat for a news conference in English and then met with a group of nearly two dozen members of the news media from Asia.

“He’s been under big pressure since he started playing the PGA Tour,” said Rex Kuramoto, who played professionally in Japan and is now a commentator for Golf Channel’s Japanese-language broadcasts. “So this pressure is nothing new to him.”

In 1977, Hisako Higuchi of Japan won the L.P.G.A. Championship in Myrtle Beach, S.C., to become the first Asian-born golfer to win a major. Higuchi was 31 years old, and upon her return to Tokyo she was feted with a ticker-tape parade. The best finish by a Japanese player in a men’s major was Isao Aoki’s second place behind Jack Nicklaus in the 1980 United States Open. Aoki, who had five top-10 finishes in majors, began the final round of the 1980 Open tied with Nicklaus, who carded a 68 to Aoki’s 70.

If Matsuyama were to end the men’s major championship wait, Kuramoto said, “it would be a big, big deal.” The men’s game in Japan is overshadowed by the women’s. Could a win here by Matsuyama flip that dynamic?

“I’m not really sure,” Matsuyama said in his news conference Friday night. “But hopefully, come Sunday, I can come back and visit you all here, and that would help increase the popularity of the men’s game in Japan.”

A version of this article appears in print on , Section SP, Page 4 of the New York edition with the headline: Matsuyama Trips Chasing a Breakthrough. Order Reprints | Today’s Paper | Subscribe